I do not need to 'use' the stems in any further form; I only use Song Master Pro to hear them isolated when there is some question while I transcribe a song.
I cannot speak about all those other programs you listed, but I thought they all use the Spleeter technology, so I would be surprised if they produce markedly different results. That's just a guess, however.
I have a number of Spleeter based apps including Ozone 11 Advanced. Spleeter doesn't do a good job separating the bass from the harmonics in the other instruments. Nothing does, really. Not hearing a bass line well enough to transcribe has never been my problem, however.
Steinberg's Spectralayers Pro does a better job but nothing is great on bass.
I used Spectralayers on a live recording I did about 25 years ago for a new recording of the same song. I was able to extract the voice of a friend who had passed away in 2008 to blend him into the chorus. On listening, I realized that my upright bass was at a similar tempo and, if isolated, would be nice to include it. My handicap precludes me from ever playing a string bass of any kind again.
I had to give up after a few hours — just couldn't get the track clean enough to re-use. Easier to play it again using VIs.